server: loosen json format constraints

readme: example/get started guide for pgai with Ollama

README.md

@@ -407,6 +407,8 @@ See the [API documentation](./docs/api.md) for all endpoints.
 
 ### Database
 
+- [PostgreSQL extension pgai](https://github.com/timescale/pgai) (Create and search embeddings from Ollama models using pgvector)
+   - [Get started guide](https://github.com/timescale/pgai/blob/main/docs/ollama.md)
 - [MindsDB](https://github.com/mindsdb/mindsdb/blob/staging/mindsdb/integrations/handlers/ollama_handler/README.md) (Connects Ollama models with nearly 200 data platforms and apps)
 - [chromem-go](https://github.com/philippgille/chromem-go/blob/v0.5.0/embed_ollama.go) with [example](https://github.com/philippgille/chromem-go/tree/v0.5.0/examples/rag-wikipedia-ollama)
 - [Kangaroo](https://github.com/dbkangaroo/kangaroo) (AI-powered SQL client and admin tool for popular databases)

llm/server.go

@@ -734,7 +734,7 @@ func (s *llmServer) Completion(ctx context.Context, req CompletionRequest, fn fu
 			}
 			request["grammar"] = string(g)
 		default:
-			return errors.New(`invalid format: expected "json" or a JSON schema`)
+			slog.Warn("invalid format: expected \"json\" or a JSON schema")
 		}
 	}